Wear behavior of contacting between thin film coating on SKD11 ball and 304 stainless steel disk

• Published in: Wārasān Songkhlā Nakharin Vol. 29; no. 6; pp. 1591 - 1598
• Main Authors: Sriprasird, J., Khantachawana, A., Premanond, V., Kaewtatip, P.
• Format: Journal Article
• Language: English
• Published: Prince of Songkla University 01.11.2007
• Subjects: coating film; friction; tribology; wear; wear rate
• ISSN: 0125-3395

Wear is a well known problem in metal stamping die, especially on the die working with stainless steel workpiece, in which wear rate is severe. This research considered various types of material coating on tool surface which were regularly practised in modern stamping industry due to the ability to increase wear resistance. The model study of friction "Ball-on-disk" technique was employed throughout this work. The disk was made from stainless steel austenitic grade (SUS304). The ball was made from cold work tool steel, SKD11 (JIS) and was hardened to 60±2 HRC. Ball surface conditions selected for this work were non-coated, coated by TiC-CVD, TiCN (TiC/TiCN/TiN Multilayer)-CVD and TiCN (TiN/TiCN Double layer)-PVD, and treated by VC-TD. Tests were carried out without lubricant. The results show that the coating film and the surface treatment has no effect on the friction coefficient but it can reduce wear rate by 64.1-99.7% at contact pressure condition less than 1,100 MPa. At the higher level of contact pressure, only 2 types of coating, TiCN (Multilayer)-CVD and TiC-CVD, can reduce wear rate. The other two, which are TiCN (Double layer)-PVD coating film and a surface treatment by VC-TD process, on the contrary increase the rate of wear significantly. This is due to delamination of coating film at high contact pressure. The coating particles of high hardness accelerate wear phenomenon on the tool surface. Therefore, proper selection of tool surface condition depends on level of contact pressure generated in the process.